thermal expansion

Hi All

I am calculating lattice parameters at various temperatures for HCP crystal using MEAM potential . I am using NPT and dumping lx,ly,lz to calculate lattice paramters .Although I see increase in lattice parameters with temperatures.My c/a ratio is constant at all temperatures and there is no anistropy thermal expansion seen for HCP crystal ?

lattice hcp 3.232
region box block 0 16 0 10 0 10

Please check out the “aniso” keyword.


FYI, aniso is an option to fix npt which will allow the c/a ratio
to vary.